Complex format specifiers

gprintf offers two format specifiers, %C and %Ci, to print a complex value. Both apply format %g separately to the real and imaginary components using any optional field modifiers that were given.

Suppose complex Z = {1.2, -3.4}.

     gprintf("%C", Z) produces the string "{1.2, -3.4}"
     gprintf("%Ci", Z) produces the string "1.2 - 3.4i"